1. Field of the Invention
The present invention relates to a panel and a method for forming the same, wherein the panel is used as an interior material such as a ceiling material of a vehicle, a door trim material of a vehicle, a back board of a seat, interior and/or exterior decorative materials of house, or insulators and boards for construction use. In particular, the present invention is directed to a panel of this kind which is formed from plant fibers of "sorghum millet", one of true grasses botanically, and a novel method for forming such panel.
2. Description of Prior Art
Hitherto, in the above-stated sorts of panels, there has been known a lamination structure of panel formed mainly from the stalks of sorghum millet, as disclosed for example from the Japanese Laid-Open Pubs. Nos. 7-16964 and 7-1409.
According to this prior art, the stalks of sorghum millet are compressed to provide plural flattened sorghum millet stalks and thereafter, such plural flattened sorghum millet stalks are so arrayed abreast with one another as to form one sheet of plate-like material. A plurality of the thus-formed plate-like materials are stacked with one another and impregnated with a melt synthetic resin for bonding them together, whereby a lamination-type panel is obtained.
Ecologically, use of sorgum millet for forming panels has been accepted as a good substitute for wood in terms of preserving forest resources, and also the use of sorghum millet has materialized production of a light and robust board. This factor is advantageously effective in forming the panel or board in a desired intricate uneven shape at a low cost in comparison with conventional plywood.
However, the foregoing prior-art panel is found defective in increasing costs in view of its entailing many steps of for treating the sorghum millet stalks, in which the stalks are subjected to impregnation with a liquid curing agent; coating with an adhesive or bonding agent; and being left to dry, for instance. Further, the process for arraying plural raw sorghum millet stalks in this prior art raises a problem of unstable quality because all the natural stalks are not always good in quality, with each of them varied in quality, as a result of which, it has been difficult not only to keep producing a predetermined strength of panel, but also to form a desired uneven three-dimensional shape of panel.